The present invention relates generally to switching power converters, and more particularly to reducing ringing at a power stage output node of a DC-DC switching power converter.
Integrated circuits generally require provision of power within particular parameters during operation. The provision of such power may face many complexities. For example, semiconductor chips including the integrated circuits may have different portions that require power at the same or different times, and which may utilize different amounts of power at different times.
DC-DC switching power converter may be often used to regulate the power provided to the integrated circuits. Some DC-DC switching power supplies utilize a power stage that includes a pair of switches serially arranged between a higher voltage source and a lower voltage source, for example between terminals of a battery serving as a power source. An output node of the power stage, for example a node between the pair of switches, may be coupled to one end of an inductor, with the other end of the inductor coupled to a load formed of the integrated circuit, in parallel to an output capacitor of the power converter.
Of the pair of switches, the switch coupled to the higher voltage source may be termed a high side switch, and the switch coupled to the lower voltage source may be termed a low side switch. In operation, the high side switch may be closed at some times (with the low side switch open), the low side switch may be closed at other times (with the high side switch open), and both switches may be open at still other times, all depending on various considerations relating to power consumption by the load and state of the power converter.
At times ringing may occur at the output node of the power stage. For example, with the high side switch and the low side switch both open, and the output node of the power stage therefore floating with respect to voltage, in discontinuous conduction mode (DCM) ringing and concomitant high frequency noise may present at the output node. This noise may have deleterious effects on provision of power to the load.